序贯载荷下考虑泊松比的药柱结构完整性分析

Structural integrity analysis of grain under sequential loads considering Poisson's ratio

为研究序贯载荷下固体推进剂泊松比变化对药柱结构的影响规律,基于线黏弹性本构方程,选取了固体火箭发动机的固化降温、立式贮存和低温点火三种典型载荷,分别进行单一载荷和序贯载荷下考虑泊松比取值变化的药柱结构完整性分析。结果表明:与单一载荷相比,序贯载荷下药柱的结构响应较为显著;序贯载荷下药柱泊松比不变时,随着工况1~6组的泊松比不断增大,固化降温和立式贮存的药柱应变也随之增大,低温点火时药柱应变随之减小,泊松比为0.497 0可满足安全性要求;序贯载荷下药柱泊松比改变时,泊松比取值较大(0.499 5、0.499 6)对固化降温和立式贮存的药柱应变影响较小,而对低温点火的药柱应变影响较大,固化降温和立式贮存时取泊松比均为0.495 0、低温点火时取0.499 5可满足安全性要求;分别计算了单一载荷和序贯载荷下随泊松比取值变化的药柱结构安全系数,前者均满足结构完整性要求,后者部分满足结构完整性要求,表明序贯载荷下得到的安全系数比较保守。

In order to study the influence of Poisson's ratio variation of solid propellants on structure of the grain under sequen⁃tial loads,structure integrity of the grain considering Poisson's ratio variation under single load and sequential loads were analyzed by selecting three typical loads of curing&cooling,vertical storage and low⁃temperature ignition of solid rocket motor based on the linear viscoelastic constitutive equation.The results show that compared with single load,the structural response of the grain under sequential loads is more significant;when Poisson's ratio of the grain under sequential loads remains constant,as Poisson's ratio of case 1~6 increases,strain of the grain under curing&cooling and vertical storage also increases,but under low⁃temperature igni⁃tion,grain strain decreases.Poisson's ratio of 0.4970 can meet safety requirements;When Poisson's ratio of the grain under se⁃quential loads changes,the larger Poisson's ratio group(0.4995,0.4996)has a smaller impact on strain of the grain under curing&cooling and vertical storage,but has a greater impact under low⁃temperature ignition.Poisson's ratio for curing&cooling and ver⁃tical storage is 0.4950,and for low⁃temperature ignition,it is 0.4995,which can meet safety requirements;the structure safety factors of the grain with Poisson's ratio variation under single load and sequential loads were calculated separately.The former meet the structural integrity request while the latter partially meet,which indicates that the safety factors obtained under sequential loads are relatively conservative.